Left Ventricular Mechanical Unloading Restores Beta-2-Adrenergic Receptor mRNA Expression and Decreases Susceptibility to Ischemia and Reperfusion in the Failing Heart
| Autor: | Yukiya Nomura, Hitoshi Horimoto, Yasunari Nakai, Shigetoshi Mieno, Kenichi Nakahara, Shinjiro Sasaki |
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| Rok vydání: | 2003 |
| Předmět: |
Male
medicine.medical_specialty Heart disease medicine.medical_treatment Ischemia Gene Expression Hemodynamics Myocardial Reperfusion Injury In Vitro Techniques Rats Sprague-Dawley Contractility Ventricular Dysfunction Left Internal medicine Animals Medicine Myocyte RNA Messenger Myocardial infarction Heart Failure Heart transplantation business.industry Recovery of Function medicine.disease Myocardial Contraction Rats Perfusion Heart failure Cardiology Heart Transplantation Surgery Disease Susceptibility Receptors Adrenergic beta-2 business |
| Zdroj: | European Surgical Research. 35:108-114 |
| ISSN: | 1421-9921 0014-312X |
| DOI: | 10.1159/000069396 |
| Popis: | Objectives: Left ventricular (LV) mechanical unloading is known to reduce the hemodynamic demands of failing LV, resulting in improved myocyte contractility. This study was designed to examine effects of LV unloading on β-adrenergic receptor (BAR) expression and ischemic susceptibility to ischemia reperfusion. Methods: Five groups were studied: group 1 [unloading myocardial infarction (MI), n = 6], MI hearts 2 weeks after coronary ligation subjected to LV unloading by heterotopic heart transplantation for 2 weeks; group 2 (2-week MI, n = 6), MI hearts left for 2 weeks without unloading; group 3 (4-week MI, n = 6), MI hearts left for 4 weeks without unloading; group 4 (control, n = 6), normal (non-MI) hearts as a control with no interventions, and group 5 (unloading control, n = 5), normal (non-MI) hearts subjected to LV unloading for 2 weeks.Then, all hearts were isolated and subjected to 20 min of global ischemia and 60 min of reperfusion on Langendorff apparatus. LV pressures and coronary flow were measured throughout the experiment. Either total BAR density or β2-adrenergic receptor (B2AR) mRNA expression in the noninfarcted myocardium was determined by radioligand binding assays or real-time quantitative RT-PCR, respectively. Results: LV unloading improved postischemic functional recovery (unloading MI vs. 2-week MI vs. 4-week MI: 74 ± 6 vs. 54 ± 5 vs. 51 ± 4%; p < 0.05 vs. unloading MI). LV unloading restored B2AR mRNA expression (unloading MI vs. 2-week MI vs. 4-week MI: 4.78 ± 0.21 vs. 2.80 ± 0.19 vs. 2.24 ± 0.17 × 107 copy/µg total RNA; p < 0.05 vs. unloading MI). Conclusion: LV mechanical unloading restored B2AR mRNA expression and improved postischemic functional recovery. |
| Databáze: | OpenAIRE |
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